Mechanical movement



Jan. 7, 1936.- E. E. FOSTER MECHANICAL MOVEMENT I Filed Aug. 27, 1934 2sheets-sheet 1 11nd E [5550;

tfii Filed Aug. 27, 1934 2 Sheets-Sheet 2 Edwin E. F0556)",

Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE MECHANICAL MOVEMENT VEdwin E. Foster, Austin, Tex. Application August 27, 1934, Serial No.741,664

10 Claims.

sible to apply a slight force or pressure toa movable element, lever,pedal, rod, wheel, etc. to accomplish a mechanical operation, and, asthe force or pressure of operation becomes greater or remains constant,the device will tend to increase its ability to deliver force orpressure so that during the entire cycle of operation of the movableelement the force or pressure necessary for operation will becounterbalanced or constant throughout. In other words, the device tendsto counterbalance the increasing or constant force or pressure of amoving element or elements so that during the entire mechanicaloperation the manual force necessary to accomplish the result desiredremains constant at approximately the same pressure or force necessaryto carryout the first part of the operation or movement.

It is a further object of the invention to provide a simple structurewhich originally stores the energy necessary to carry out an increasingor constant force or pressure in accomplishing a mechanical operation.

The device is particularly applicable in operating clutch and brakepedals for motor vehicles, in assisting in the movement of heavyobjects, the movement or placement of objects to a desired point orplace and their return, for counterbalancing the action of a returnspring or the force of a spring in general, etc. In connection with theoperation of a clutch pedal, for instance, a mechanical movementaccording to the present invention renders it possible to reduce theentire pressure of operation to aminimum without sacrificing the controlwhich the operator has or needs over the vehicle or its operation. Alsothe mechanical movement is applicable to ironing machines of all typesto counterbalance the weight of the iron or head of a laundry machine orpresser so that very little manual labor is necessary in lowering andraising an iron or the head of a laundry machine.

Other objects will be apparent from the following description taken inconnection with the accompanying drawings, in which:

Figure l is a diagrammatic side view of the mechanical movement showingthe parts or elements at rest or at the beginning of operation, in whichthe energy is stored in one spring,

Fig. 2 is a similar view showing the parts just before the workingstroke in which the energy has been transferred to the other spring, and

Fig. 3 is a similar view showing the completion of the power stroke. 7

For purpose of illustration the mechanical movement is mounted on andforms a part of a movable frame member or a four bar linkage l4, l5, l6and ll, of which the member M is stationary. An arm I is fixed to themember or bar [4 and to which one end of a cable 2 is secured at 25. Theother end of the cable 2 is secured at 4 5 to the periphery of aneccentrically mounted wheel or pulley 3. The pulley 3 is rotatablymounted on an axle is at the meeting or pivot point of the bars l6 andH. At the point 4 on the pulley 3 another cable 20, or the same cable 2,10 is secured which has the other end 6 secured to one end of a spring5. The other end of the spring 5 is secured to another cable 2| whichpasses around, depending upon the position of the parts of themechanical movement, and is se- 15 cured to the periphery of theeccentrically mounted pulley I 0 at 1. This cable 2|, or another sectionof cable 22, passes from the point 1 to one end of a second spring 8 at23. The spring 8 is secured at the other end to the bar H5 at 9. Bothsprings 8 and 5 are tension springs which will be more fully describedin the operation of the device.

The pulley It) is eccentrically mounted on a pivot or axle l3 on the barl6. Furthermore, on 25 the axle l3 and secured to and rotating with thepulley I0 is an auxiliary or small pulley I2 around which a cable I l iscapable of being wound. One end of the cable H is secured to the pulleyI2 at 24; 30

If, for instance, single lengths of cable are used attached to thesprings instead of a number, the cables must be secured to the peripheryof the pulleys at 4 and l. f

The operation of the device is as follows:

7 In normal position the various elements are shown as indicated in Fig.l. The spring 8 is under tension or in other words it has energy storedtherein. The spring 8 is pulling, by means of cable 22, against a shortlever arm, due to the position of the pulley H] on its axle l3. Thespring 5 which is slightly under tension is pulling against a long leverarm, the long lever arm being theoretically considered as a line passingfrom the center of the axle l3 upwardly to the periphery of the pulleyand the short lever arm by a line passing down from the center of theaxle to the periphery .of the pulley H1.

The other end of spring 8 is pulling on bar l6 at 9, to which it isattached, and at 5 the spring 5 g is pulling around the eccentricallymounted pulley 3. The four bar linkage is maintained stationary, that isfrom collapsing toward the right, Fig. 1, due to the cable 2 which issecured to the stationary arm I.

When the control cable II is pulled in the direction of the arrow, whichpull is rather slight, the pulley It] will be rotated counter-clockwiseapproximately one-half of a revolution so that the various elementschange their positions from those shown in Fig. 1 into those shown inFig. 2. In such position the energy stored in spring 8 is changed overinto the spring 5 so that the latter is tensioned and spring 8 assumes acompressed appearance. It will be noted that while in Fig. 1 the cable22 contacts approximately one-half of the periphery of the pulley ID,the cable 2| in the new position contacts approximately one-half theperiphery of the pulley, the cables 20 and 2 and the pulley 3 remainingpractically unchanged relative to these elements to each other.

In the further operation of the mechanical movement, assuming that aslight pull is still being exerted on the cable H, the tension in thespring 5 will 'now cause the pulley 3 to rotate counter-clockwiseapproximately one-half a revolution thereby causing the elements toassume the positions shown in Fig. 3. In the latter position of themechanical movement the power stroke has been exerted on the bar I5causing a rotation in the shaft iii, to the latter of which is attachedthe element or elements, the force or pressure of which is to becounterbalanced. It will be noted in Fig. 3, that the pulley 3 hasrotated approximately one-half of a revolution and the four bar linkagehas shifted toward the left, the bar I4 of course being stationary atall times. Also the spring 5 has assumed a compressed appearance sincethe energy stored therein from spring 8 has been transformed into workby rotating shaft l8 to counterbalance the force or pressure desired.

To return the parts to the original or nor.- mal position as shown inFig. 1 the slight tension on cable H is released and the operation isreversed, that is the energy stored in the cooperating parts, not shown,of shaftl8 restore such energy back into spring 5 and from there intospring 8.

The amount of eccentricity of the pulleys 3 and I0 and the shapesthereof are matters of design depending upon the forces and pressures tobe dealt with and the specific type of machine with which the mechanicalmovement is used. Also the eccentrically mounted pulleys 3 and I0 andparticularly pulley 3 can be egg-shaped or may have any other irregularperiphery to adapt the device for any specific operation where the forceis to be increased and for other conditions. The cable H can also bedispensed with as a shaft, not shown, or axle [3 can be employed torotate the small pulley 12.

It is also possible to construct the movement so that the cables 2, 28,2!, and 22 may becomposed of the material of the springs with the temperremoved by elongations on the springs.

I claim as my invention:

1. A mechanical movement comprising a movable frame member, a pair ofpulleys eccentrically mounted on the frame member, a cable system forthe pulleys, a pair of springs mounted in said cable system, one springin the normal position being under considerable tension and the otherunder slight tension, and means for rotating one of said pulleys totransfer the energy in the considerably tensioned spring into theslightly tensioned spring to perform a working stroke by utilizing theenergy in the lastm en'tioned spring. 7 I 2. A mechanical movementaccording to claim 1 in which the movable frame member is in-the form ofa four bar linkage of which one bar is stationary.

3. A mechanical movement according to claim 1, in which the meansincludes a small pulley mounted on one of the eccentrically mountedpulleys and provided with a cable which when sufficient force is appliedthereto the eccentrically mounted pulley will be rotated.

slightly tensioned spring to perform a working stroke by utilizing theenergy in the last-mentioned spring.

5. A mechanical movement comprising a movable frame, a pair of pulleyseccentrically and rotatably mounted on the frame member, a pair ofsprings cooperating with said pulleys and one spring being under tensionin the normal position and means for rotating one of said pulleys totransfer the energy in the tensioned spring to the other spring toperform a working stroke by utilizing the energy in the last-mentionedspring.

6. A mechanical movement according to claim 5, in which the meansincludes a small pulley mounted to rotate with one of the eccentricallymounted pulleys and provided with means which when sufiicient force isapplied thereto the lastmentioned eccentrically mounted pulley will berotated to transfer the energy from the tensioned spring to the otherspring.

7. A mechanical movement comprising a pair of bars pivotally mounted atone end, a third bar pivotally mounted on the other ends of the pair ofbars, a pair of pulleys eccentrically and rotatably mounted on the bars,a pair of springs, a cable connected to the springs and to and aroundthe pulleys, one spring being under considerable tension and the otherunder slight tension in the normal position, and means for rotating oneof said pulleys to transfer the energy in the tensioned spring to theother spring to perform a working stroke by utilizing the energy inthelast-mentioned spring.

8. A mechanical movement according to claim 10, in which the meansincludes a small pulley mounted to rotate with one of the eccentricallymounted pulleys and provided with a cable secured to theperiphery of thesmall pulley which when sufficient force is applied thereto the smallpulleyand the pulley to which it is secured will be rotated to transferthe energy from the considerably tensioned spring to the slightlytensioned spring.

' 9. A mechanical movement according to claim CERTIFICATE OF CORRECTION.

Patent NO. 2,027,275.

EDWIN E. FOSTER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second column, line 52, claim 8, for the numeral "10" read '7; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 11th day of February, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

January 7, 1936.

